Luminous efficacy enhancement for LED lamps using highly reflective quantum dot-based photoluminescent films

In this study, a strongly reflective and photoluminescent (PL) poly(lactic-co-glycolic acid) quantum dot (QD) hybrid nanofiber (PQHN) structure is introduced to enhance the luminous efficacy of QD-phosphor hybrid white light-emitting diodes (QD-WLEDs). As the thickness of PQHN film increases, the PL is found to continuously increase, exhibiting a maximum peak intensity at 120 μm, which is 1.92 times that at 12 μm, and showing the highest diffuse reflectance of 94.4% at 640 nm. Consequently, while using the QD-WLEDs, the PQHN structure achieves a 53.8% improvement in luminous flux compared with the traditional structure under a similar correlated color temperature (CCT) of 3,540 K, achieving a high luminous efficacy of 202.11 lm W^-1 for QD-WLEDs. In addition, the maximum deviation of the CCT is only 11 K when the current is changed from 50 to 950 mA, demonstrating good stability. Therefore, the PQHN films have great potential in lighting systems as a hybrid functional film including light conversion and reflectance.